This study will investigate the effects on body composition and metabolism of changing therapy from a protease inhibitor to a potent non-nucleoside HIV revers transcriptase. The most common and serious complication of PI based on regiments fro treatments of HIV involve a spectrum of clinical disorders associated with fast wasting, increases in intra-abdominal visceral fat, increases in LDL cholesterol, decreases in HDL cholesterol, increases in triglycerides, and insulin resistance. These complications increase the risk of morbidity and mortality.